Based on previous experience with Morris hepatomas and autochthonous hepatomas produced by the Peraino protocol for initiation with acetylaminofluorene (AAF) and promotion with phenobarbital (PB), we have set up a long duration experiment based on only 2 weeks exposure of 21-day old male rats to AAF at 0.015%, 0.030% and 0.045% in a semi-purified diet followed by the same diet alone or with PB, plus or minus partial hepatectomy, with sufficient animals to permit shifting from PB to basal at 150 and 250 days for either 100 or 200 days. Parallel groups of female rats were also in the protocol. These animals will be used for studies on AIB transport and additional enzyme studies. Meanwhile studies on AIB transport in cell cultures of four hepatoma lines and on normal hepatocytes are being studied under conditions of induction or repression by dexamethasone, insulin, glucagon, amino acids and cyclic AMP. O'Farrell methods for 2 dimensional protein separations have been stablished and are now being applied to extracts from normal and hepatoma cell cultures after 35S-methionine and autoradiography of newly-synthesized proteins.